From 7e135add24911a9302d9e73fe0456318ce8169fa Mon Sep 17 00:00:00 2001 From: Rui Salvaterra Date: Sun, 22 Aug 2021 14:50:07 +0100 Subject: kernel: disable CONFIG_RCU_EXPERT and friends Based on the existing documentation [1][2], I dare anyone to demonstrate that we need to fine-tune these RCU parameters. The (performance) breakage potential for doing so is immense, so let's just please put down this loaded footgun. Disable CONFIG_RCU_EXPERT and its dependent symbols. Additionally, remove the CONFIG_RCU_EXPERT symbol from the target kconfigs which contain it. [1] https://www.kernel.org/doc/Documentation/RCU/Design/Data-Structures/Data-Structures.html [2] https://lwn.net/Articles/777214/ Signed-off-by: Rui Salvaterra --- target/linux/generic/config-5.10 | 7 +------ target/linux/generic/config-5.4 | 6 +----- 2 files changed, 2 insertions(+), 11 deletions(-) (limited to 'target/linux/generic') diff --git a/target/linux/generic/config-5.10 b/target/linux/generic/config-5.10 index f944f1718f..91f137fbc3 100644 --- a/target/linux/generic/config-5.10 +++ b/target/linux/generic/config-5.10 @@ -4631,12 +4631,8 @@ CONFIG_PWRSEQ_SIMPLE=y CONFIG_RCU_CPU_STALL_TIMEOUT=60 # CONFIG_RCU_EQS_DEBUG is not set # CONFIG_RCU_EXPEDITE_BOOT is not set -CONFIG_RCU_EXPERT=y -CONFIG_RCU_FANOUT=32 -CONFIG_RCU_FANOUT_LEAF=16 -# CONFIG_RCU_FAST_NO_HZ is not set +# CONFIG_RCU_EXPERT is not set CONFIG_RCU_KTHREAD_PRIO=0 -# CONFIG_RCU_NOCB_CPU is not set # CONFIG_RCU_PERF_TEST is not set # CONFIG_RCU_REF_SCALE_TEST is not set # CONFIG_RCU_SCALE_TEST is not set @@ -5995,7 +5991,6 @@ CONFIG_SYSVIPC_SYSCTL=y # CONFIG_TARGET_CORE is not set # CONFIG_TASKSTATS is not set # CONFIG_TASKS_RCU is not set -CONFIG_TASKS_TRACE_RCU_READ_MB=y # CONFIG_TASK_XACCT is not set # CONFIG_TC35815 is not set # CONFIG_TCG_ATMEL is not set diff --git a/target/linux/generic/config-5.4 b/target/linux/generic/config-5.4 index 45d8f0976e..06f5e43a6d 100644 --- a/target/linux/generic/config-5.4 +++ b/target/linux/generic/config-5.4 @@ -4262,12 +4262,8 @@ CONFIG_PWRSEQ_SIMPLE=y CONFIG_RCU_CPU_STALL_TIMEOUT=60 # CONFIG_RCU_EQS_DEBUG is not set # CONFIG_RCU_EXPEDITE_BOOT is not set -CONFIG_RCU_EXPERT=y -CONFIG_RCU_FANOUT=32 -CONFIG_RCU_FANOUT_LEAF=16 -# CONFIG_RCU_FAST_NO_HZ is not set +# CONFIG_RCU_EXPERT is not set CONFIG_RCU_KTHREAD_PRIO=0 -# CONFIG_RCU_NOCB_CPU is not set # CONFIG_RCU_PERF_TEST is not set # CONFIG_RCU_TORTURE_TEST is not set CONFIG_RCU_TORTURE_TEST_SLOW_INIT_DELAY=3 -- cgit v1.2.3